Fluid-structure interactions in the physiologic aortic root between flexible valve leaflets, dynamic aortic root, compliant aorta and pulsatile blood flow influence valve performance. In certain aortic valve-sparing operations, the aortic root is replaced by rigid, tubular grafts. The effect of this replacement on valve performance has not been investigated yet. We propose to study this phenomenon by developing a computational aortic valve test chamber (CAVT) for natural/bioprosthetic valves. In Phase I, we developed a preliminary two-dimensional model for describing interactions between natural valve leaflets and pulsatile blood flow. In Phase II, dynamics of the aortic root and ascending aorta compliance will be incorporated in this preliminary model. It will then be extended for three-dimensional simulations of natural and bioprosthetic valve dynamics. In vivo model predictions will be validated against published data. In vitro predictions of tissue valve performance with, and without, the sinuses will be validated experimentally. To complete the CAVT, a graphical-user interface will be developed for the model. The CAVT will then be used to study the effects of sinus geometry, aortic root dynamics and aortic compliances on natural valve dynamics. Finally, design criteria will be developed for optimal non-tubular aortic root grafts for use with native valves.